Method for producing a high-molecular weight flocculant

ABSTRACT

A high-molecular flocculant rendered water-soluble by conversion of cyano groups contained in a high-molecular material, a method for producing the flocculant, and a method for efficiently processing water using the flocculant. A high-molecular material containing acrylonitrile as a monomer is processed safely to impart hydrophilicity to the material and the resulting product is used for water processing to contribute to environmental conservation. An amino compound is added to a cyano group containing high-molecular material to convert at least a portion of the cyano group (—C≡N) into a molecular structure portion having an imidamino structure and, if necessary, to convert at, least the portion into one of an acid salt, a quaternary ammonium salt or a hydrolyzate structure portion to give a high-molecular flocculant. Alternatively, a high-molecular material having cyano groups is hydrolysed to convert the cyano group into carbamoyl groups, carboxylic groups or their salts to give a high-molecular flocculant. This high-molecular flocculant is charged alone or in combination the water for processing various.

BACKGROUND OF THE INVENTION

[0001] This invention relates to a high-molecular flocculant renderedwater-soluble by conversion of cyano groups contained in ahigh-molecular material, a method for producing the flocculant, andmethod for efficiently processing water using the flocculant.

DESCRIPTION OF THE RELATED ART

[0002] In the field of processing waste water, a flocculant is used as areagent for causing aggregation and precipitation of micro-sizedparticles dispersed in waste water. In the waste water, such asindustrial waste water, it is a frequent occurrence that mud orhigh-molecular impurities are dispersed as colloidal particles. Theflocculant serves for aggregating these colloidal particles forpurifying the polluted water.

[0003] Of the wide variety of known flocculants, those having amolecular structure of a long chain and exhibiting high hydrophilicityare high-molecular flocculants which are used extensively becauseaddition of only a limited amount thereof to the colloidal particlesleads to significant aggregating effects. The high-molecular flocculantsare classified into an anionic type, a cationic type and a nonionic typedepending on static charges on dissolution in water. Since a majority ofcolloidal particles are charged to the positive or negative polarity,extremely large flocs are formed to lower the turbidity highlyefficiently by properly selecting the high-molecular flocculantsdepending on the polarity of the static charges.

[0004] In the field of manufacturing industrial products, high-molecularmaterial, containing acrylonitrile as a monomeric unit, are usedextensively. Among the high-molecular materials containingacrylonitrile, there are polystyrene based resins, typified by nitriteresins, ABS (acrylonitrile-butadiene-styrene resins), SAN resins(styrene-acrylonitrile resin), AAS resins (acrylonitrile-acryl-styreneresins) and ACS resins (acrylonitrile-chlorinated polyethylene-styreneresin), acrylic fibers obtained on spinning a polymer havingacrylonitrile as a main monomeric unit, and NBR (acrylonitrile-butadienerubber, also termed nitrite rubber).

[0005] A resin molded product, containing acrylonitrile as monomericunits, is superior in stiffness, dimensional stability and workabilityand hence is used frequently as a cover or a casing for various usages,a casing for an electric appliance or a car or as a material forcomponents.

[0006] The acrylic fibers are lightweight, bulky and is excellent inheat insulating properties, skin touch feeling, weatherability andresiliency, so that they are used extensively for apparel alone or as amixture with other fibers, such as wool or cotton.

[0007] The nitrite rubber exhibits superior weatherability against oils,such as fuel oil, machine oil or a tube oil, so that it is used as afuel hose, oil seal or a belt and in particular for car use.

[0008] The acrylonitrile containing high-molecular material, used in awide variety of industrial products, produces a large quantity of wastematerials in the course of fabrication of the industrial products or ondiscarding of the used-up industrial products. The waste high-molecularmaterials are generally disposed of by techniques such as incineration,earth filling or re-melting. The former two technique belongs todiscarding, while the later technique belongs to recycling.

[0009] The above-mentioned disposal techniques for the high-molecularmaterial suffer from specified problems.

[0010] First, the incineration is accompanied by the problem ofevolution of toxic gases during combustion of the waste material. Thatis, highly toxic cyan gas (HCN) is evolved due to cyano groups (—C═N)contained in the acrylonitrile monomer unit and which constitutes one ofside chains of the polymer. Another factor contributing to incinerationdifficulties is susceptibility to conversion into incombustible matteras a result of carbonization.

[0011] Re-melting is a technique of heat-melting the recovered wastematerial for re-molding, and represents an effective technique insofaras thermoplastic resins are concerned. However, the material tends to bedeteriorated in quality due to lowering in the molecular weight oroxidation, while being liable to mixing of foreign matter, such as dustand dirt. If waste materials of different originating points areprocessed collectively, technical and cost problems are raised, such asthe necessity of re-coloring due to coexistence of various coloringagents.

[0012] Thus, discarding by land filling is nowadays thought to be mostproper measures. However, selection and procurement of the proper sitefor a processing plant is becoming difficult from year to year, whilethe problem of environmental pollution cannot be evaded withoutdifficulties.

SUMMARY OF THE INVENTION

[0013] It is an object of the present invention to provide a method formanufacturing a high-molecular flocculants having superior flocculatingproperties by a simple and safe manner using the high-molecular materialcontaining cyano groups as a starting material and a method foreffective disposal of waste water employing this high-molecularflocculant.

[0014] The high-molecular flocculant of the present invention, proposedfor accomplishing the above object, is such a flocculant in which atleast a portion of cyano groups (—C—N) contained in the high-molecularmaterial is converted to impart water-solubility to enable the use ofthe material as a flocculant.

[0015] Specifically, in one aspect, the present invention provides ahigh-molecular flocculant having a molecular structure portion comprisedof an organic and/or inorganic amino compound added to at least aportion of cyano groups contained in a high-molecular material.

[0016] In another aspect, the present invention provides ahigh-molecular flocculant in which at least a portion of cyano groupscontained in a high-molecular material has been converted into carbamoylgroups.

[0017] The former flocculant can be prepared by reacting the cyano groupcontaining high-molecular material with an amino compound, while thelatter can be prepared by hydrolyzing the cyano group containinghigh-molecular material.

[0018] In particular, if a used-up waste material from some otherprocess is used as a high-molecular material for use as a startingmaterial, resources can be exploited effectively by recycling thuscontributing to environment conservation.

[0019] The high-molecular flocculant, thus obtained, can be injectedinto water for processing for water processing as a cationic or nonionictype high-molecular flocculant. It may also be used in conjunction withother nonionic, anionic or cationic high-molecular flocculant.

[0020] It is seen from above that the high-molecular flocculantaccording to the present invention is obtained as a result ofhydrophilicity-imparting modification of the high-molecular materialcontaining cyano groups, in particular cyano groups originating fromacrylonitrile. Since the high-molecular material is likely to beproduced in large quantities as industrial wastes, the present inventionis highly effective in reducing toxic waste materials and effectiveutilization of resources.

[0021] Moreover, since this modification of the high-molecular materialis achieved by addition of an amino compound or by a hydrolyticreaction, there is caused no problem such as emission of toxic gasesduring incineration thus evading the problem of new environmentalpollution in the course of processing of waste materials. In addition,the high-molecular flocculant obtained as a result of processing of thewaste materials exhibits superior properties in connection with the rateof flocculation, turbidity of the supernatant liquid or in the watercontent of the cake. Therefore, use of the high-molecular flocculantobtained as a result of processing of the waste materials, for waterprocessing, leads to re-utilization of the usually discarded wastematerials, thus contributing not only to reduction of the toxic wastematerials and effective utilization of resources, but to environmentalconservation through purification of waste water.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022]FIG. 1 illustrates the mechanism for addition reaction, saltforming reaction and hydrolysis in connection with manufacture of ahigh-molecular flocculant of the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0023] The high-molecular flocculant of the present invention isobtained by introducing a highly hydrophilic molecular structure into atleast a portion of cyano groups inherently contained in thehigh-molecular material or by subsequently carrying out salt formationor hydrolysis in case of necessity for adjusting water-solubility orflocculating properties. If it is desired to impart sufficienthydrophilicity to the yielded high-molecular flocculant or to precludeyielding of hydrogen cyanide with a view to safe waste discarding, it ispreferred that the majority of cyano groups shall be converted into ahighly hydrophilic molecular structure portion.

[0024] The highly hydrophilic molecular structure portion may beexemplified by a molecular structure portion having added inorganic ororganic amino compounds or carbamoyl groups formed by hydrolysis ofcyano groups.

[0025] As the amino compounds added to the cyano group in the formercase, there are, for example, inorganic amino compounds, such asammonia, hydrazine or hydroxylamine, and organic amino compounds, suchas primary or secondary amines in which one or two hydrogen atoms ofammonia are substituted by hydroxy groups. The carbon skeleton of thehydrocarbon group may be saturated or non-saturated, of a chain orcyclic structure, straight-chained or branched. It is also possible forhetero elements other than carbon, hydrogen or nitrogen, such as oxygen,sulfur or halogens, to be contained in the skeleton of the hydrocarbongroup.

[0026] Examples of the organic amino compounds include primary orsecondary amines, substituted by C1-C12 saturated or unsaturated chainedor cyclic hydrocarbon groups, primary or secondary amines containing twoor more amino groups in one molecule and the aforementioned primary andsecondary amines containing hetero atoms other than nitrogen in themolecule.

[0027] The primary and secondary amines containing two or more aminogroups in one molecule may be enumerated by alkylene diamines, such asmethylene diamine, ethylene diamine, trimethyl diamine (diaminopropane), tetramethylene diamine (diamino butane), pentametylene diamine(diamino pentane), hexamethylene diamine (diamino hexane) orhexamethylene diamine (diaminoheptane), N-alkyl alkylene diamines, suchas N-methyl methylene diamine, N-methyl ethylene diamine, N-benzylethylene diamine, N-methyl-1,3-diamino propane, N-butyl-1,3-diaminopropane, N-dimethyl-1,3-diamino propane or N-butyl-1,3-diamino propane,alkylene polyamines (not less than three substituents), such asdiethylene triamine, triethylene tetramine, tetraethylene pentamine,pentaethylene hexamine, polyethylene imine or piperidine and cyclicpolyamines, such as 1,2-diamino cyclohexane, xylylene diamine anddiamino diphenylmethane.

[0028] The amino compounds containing hetero atoms other than nitrogenin the molecule may be enumerated by hydroxyl alkylamines, such asethanolamine, propanolamine, butanolamine and pentanolamine. Ethanethiolamine may also be used.

[0029] Although there is no limitation to the amino compounds, polyaminecompounds, in particular ethylene diamine or 1,3-propane diamine, arepreferably used for reaction with the high-molecular material since thepolyamine compound can yield an imidazoline ring by reaction with cyanogroups.

[0030] The molecular structure portion, yielded by addition of anorganic or inorganic amino compound, has an imidamino or imidazolinestructure, and exhibits basicity due to the lone electron pair on thenitrogen atom.

[0031] If this nitrogen atom is linked by coordinate bond to a protonfurnished from the inorganic or organic acid, the nitrogen atom ischarged positively to yield an acid salt. An inorganic acid, such assulfuric acid, chlorosulfonic acid, chloric acid, nitric acid orphosphoric acid may be used. As an organic acid, acetic acid, lacticacid, phthalic acid or phenols may be used.

[0032] If a halogenated hydrocarbon or sulfuric acid ester is given themolecular structure portion, the nitrogen atom of the molecularstructureportion is linked to the hydrocarbon group of sulfuric acid ester or thehalogenated hydrocarbon so as to be charged positively to yield aquaternary amine salt having the halogen as paired ions. The halogenatedhydrocarbon used at this time mat be enumerated by methyl chloride orbenzyl chloride, while the sulfuric acid ester may be enumerated bydimethyl sulfide or diethyl sulfide.

[0033] These acid salts and quaternary ammonium salts exhibit high watersolubility.

[0034] On the other hand, the latter (hydrophilic groups such ascarbamoyl group) is yielded by replacing at least a portion of thestrongly hydrophobic cyan group inherently contained in thehigh-molecular material by a hydrophilic group, that is a carbamoylgroup (CONH2) or by a carboxyl group (—COOH) or salts thereof (—COOX,where X is a cation).

[0035] This carbamoyl group or the carboxyl group is obtained byconversion of a functional group by a hydrolytic reaction. Thisconversion of the functional group occurs in the sequence of a cyangroup—a carbamoyl group—a carboxyl group (or a salt thereof).

[0036] As a matter of course, it is necessary for the cyano group to becontained in the high-molecular material as a starting material for thehigh-molecular flocculant of the present invention in a form allowingaddition thereto of ammonia or an amino compound or in a form allowingfor substitution by a hydrophilic group. A high-molecular materialcontaining acrylonitrile (CH2═CH—CN) is preferred because the cyanogroup is linked as a side chain of the polymer molecule.

[0037] The molecular structure portions yielded on addition of ammonia,hydroxylamine, ethylene diamine, primary alkyl amine and ethanolamine tothe cyano group of the acrylonitrile monomer unit are collectively shownin FIG. 1, along with structures obtained on yielding of the imidazolinering by the action of ethylene diamine, acid salts, quaternary ammoniumsalts yielded on hydrolysis.

[0038] The above-mentioned high-molecular material may also becopolymers with other monomeric units (copolymers) without being limitedto acrylonitrile homopolymers. These other monomeric units may beenumerated by one or more selected from the group consisting of acrylicacid, methacrylic acid, acrylic acid ester, methacrylic acid esters,butadiene, isoprene, chloroprene, vinyl chloride, acrylic amide,methacrylic amide, vinyl acetate, styrene, a-methyl styrene, ethylene,propylene, fumaric anhydride, malefic anhydride, itaconic anhydride,N-vinyl pyrrolidone and vinyl pyridine. The side chain of the ester bondof the acrylic acid ester and methacrylic acid ester is preferablyconstituted by saturated or unsaturated hydrocarbons having 1 to 10carbon atoms.

[0039] Among representative high-molecular materials, obtained oncombining acrylonitrile with the above-mentioned other polymers, thereare, for example, acrylic fibers, nitrite fibers, SAN resins(styrene-acrylonitrile resins), acrylonitrile-butadiene resins,acrylonitrile-butadiene-styrene resins, acrylonitrile-butadiene-acrylicresins, acrylonitrile-chlorinated polyethylene resin, nitrite rubber andacrylonitrile-butadiene rubber.

[0040] Meanwhile, if the above-mentioned high-molecular material is anacrylonitrile homopolymer, the content of the cyano groups is 100 mol %.However, if the high-molecular material is the acrylonitrile copolymer,the content of the cyano groups naturally is varied depending on thecontent of the acrylonitrile monomer unit. If the content of the cyanogroups is varied, the upper limit of the number of mots of the molecularstructure portion yielded by the addition reaction of the amino compoundand further the upper limit of the structure of hydrolysis yielded bychanges in the salt the molecular structure portion can yield or in themolecular structure portion are changed. Similarly, if the content ofthe cyano groups is changed, the upper limit of the number of mots ofthe carbamoyl group introduced later, the carboxylic group introduced inplace of the carbamoyl group on or the salts thereof are changed.

[0041] That is, if the content of the cyano groups is inherently small,the high-molecular flocculant of the present invention cannot exhibithigh hydrophilicity or flocculating properties.

[0042] That is, according to the present invention, it is preferred thatthe cyano groups be contained in the high-molecular material in anamount corresponding to not less than 15 mol % of the total monomerunits, that is that the content of the acrylonitrile monomer units benot less than 15 mol %. This amount is preferably not less than 25 mol%.

[0043] Meanwhile, the high-molecular material has the weight averagemolecular weight (Mw) of approximately not less than 5000. If themolecular weight is lower than this limit value, the flocculatingproperties as the high-molecular flocculant tend to be lost.

[0044] The high-molecular material, as the starting material for thehigh-molecular flocculant according to the present invention, may, ofcourse, be a newly prepared material, that is a so-called virginmaterial. However, from the viewpoint of effective utilization ofnatural resources and prevention of environmental destruction, it isparticularly desirable to use a used-up waste material.

[0045] These waste materials may be exemplified by, for example, acasing, a cover or a vessel used in electric appliances, cars,stationery, measurement instruments, building materials or in cosmetics.The waste materials may be in the form of a mixture with other wastematerials. Examples of these other waste materials include synthetic ornatural fibers, such as polyester, nylon, polyurethane, polyamides,polyphenylene ether, polycarbonates, polyphenylene sulfide, polyethyleneterephthalate, polybutylene terephthalate, silk, wool or cotton,occasionally containing a variety of additives, such as coloring agents,stabilizers, water retention agents, combustion retardants, plasticizersor fillers.

[0046] If the above-mentioned other waste materials are used inconjunction, the content of these other waste materials is preferablynot more than 60 wt %. If the content exceeds 60 wt %, the effect of thefunctional groups is strongly demonstrated such that desired watersolubility is occasionally not imparted to the yielded high-molecularflocculant.

[0047] Thus, although the waste materials may be those recovered fromfactories, retail stores or homes, the waste materials from factories orretail stores, where waste materials of the unitary composition arelikely to be produced in larger quantities, are more desirable thanthose recovered from holes and in which foreign waste materials tend tobe mixed more readily.

[0048] Turning to the method for producing the high-molecular flocculantof the present invention, if the high-molecular flocculant has amolecular structure portion comprised of organic and/or inorganic aminocompounds added to at least a portion of the cyano groups contained inthe high-molecular material, it is sufficient if the above-mentionedacrylonitrile homopolymer or copolymer is used as a starting materialand is reacted with the organic and/or inorganic amino compounds.

[0049] This reaction can be carried out by directly injecting thestarting material into the amino compounds. After the end of thereaction, it is possible to pour a solvent in which the high-molecularflocculant is not soluble, such as acetone, into the reaction mixture inlarge quantities to re-precipitate the product.

[0050] Alternatively, the reaction can be carried out in an organicsolvent, which may be a CS to C20 aliphatic chain hydrocarbon and/orcyclic hydrocarbon, C1 to C4 halogenated hydrocarbons, dichlorobenzene,aromatic hydrocarbons, ethers, ketones, esters, or non-protonic polarsolvents, such as dimethyl sulfoxide (DMSO), dimethyl formamide (DMF),tetrahydrofuran (THF) or dioxane. If the organic solvent is used, thereaction product may be obtained as an aqueous solution by adding waterto the reaction system and distilling off the solvent after the end ofthe reaction.

[0051] During the reaction, sulfur-based catalysts, such as sulfurpowders, thiourea or thioacetoamide, are preferably used.

[0052] Although there is no limitation to the concentration of the aminocompound during the reaction, it is preferably not lower thanapproximately 10%. If this concentration is too low, the speed of theaddition reaction tends to be lowered, or the reaction of addition tendsto be retarded. There is also no upper limit to the above concentration.If the reaction of addition is carried out by injecting a small amountof the high-molecular material into ethylene diamine, the concentrationof ethylene diamine is approximately 100%.

[0053] The reaction temperature for the reaction of addition differswith the type of the high-molecular material used as the startingmaterial, type of the catalyst used, type of the solvent used for thereaction system and with whether or not the solvent is used. If thereaction temperature is 0 to 150° C., the reaction is allowed to proceedwith practically acceptable speed and controllability. If thetemperature is lower than this range, the reaction speed is lowered thuspossibly lowering the production efficiency. Conversely, if thetemperature is higher than the above range; the high-molecular materialtends to be lowered in molecular weight to lower the efficiency as theflocculant. This temperature range is preferably 20 to 120° C. and mostpreferably 40 to 80° C.

[0054] As for the reaction time duration, which depends on the type ofthe amino compound used, the reaction time of 30 minutes to 50 hours cangive a target product with a practically acceptable yield. If thereaction time duration is shorter than this range, sufficientmodification cannot be achieved. However, if once the chemicalequilibrium is reached, prolongation of the reaction time has nomeaning.

[0055] If, in the present invention, hydrolysis is to occur after theaddition reaction of the amino compound, it can be carried out by acidhydrolysis employing an acid catalyst or alkali hydrolysis employing abasic catalyst.

[0056] As the acidic catalyst for acidic hydrolysis, inorganic acids,such as sulfuric acid, sulfuric anhydride, fuming sulfuric acid,chlorosulfonic acid, hydrochloric acid, nitric acid or phosphoric acid,may be used. These inorganic acids may be used in conjunction withinorganic peroxides, such as aqueous hydrogen peroxide, in order topromote the hydrolytic reaction.

[0057] As the basic catalyst for the alkaline hydrolysis, hydroxides,hydrogen carbonates, carbonates or acetates of Li, Na, K or NH₄ may beused.

[0058] In any type of the alkaline hydrolysis, the high-molecularmaterial may be directly injected into inorganic acids, or into anaqueous alkaline solution of an inorganic base. Alternatively, thehydrolysis may be carried out using the same solvent as that used forthe above-mentioned reaction of addition. The catalyst concentration,reaction temperature or the reaction time for hydrolysis may be setequivalently to the respective ranges discussed in connection with theabove-mentioned reaction of addition.

[0059] The high-molecular flocculant, resulting from the above process,is of the nonionic type in the stage in which it has acquired themolecular structure portion directly after addition of the aminocompound, and is of the strong cation type on converting this molecularstructure portion into an acid salt or a quaternary ammonium salt. Thatis, with the above-described manufacturing method of the high-molecularflocculant, it is possible to produce flocculants of the nonionic typeand the cationic type by judiciously selecting and combining the stagesof the progress of the reaction of addition and the salt-formingreaction.

[0060] For converting the cyano group for introducing carbamoyl groups,carboxylic groups or salts thereof, the aforementioned acrylonitrilehomopolymers or copolymers are used as the starting material, that is asa basic material for hydrolysis.

[0061] The hydrolysis is roughly classified into an acidic hydrolysisemploying an acidic catalyst and hydrolysis employing the basiccatalyst. Any of these hydrolysis types may be used in the presentinvention.

[0062] As the acidic catalyst for the above-mentioned acidic hydrolysis,inorganic acids, such as sulfuric acid, sulfuric anhydride, fumingsulfuric acid, chlorosulfonic acid, hydrochloric acid, nitric acid orphosphoric acid, may be used. These inorganic acids may be used inconjunction with inorganic peroxides, such as aqueous hydrogen peroxide,in order to promote the hydrolytic reaction. Since the acidic hydrolysisof the high-molecular material containing cyano groups is satisfactoryin controllability, the reaction itself can be carried out in one stepby properly selecting the reaction temperature and the reaction time sothat a desired content of the carbamoyl groups will be achieved.

[0063] Although there is no particular limitation to the concentrationof the inorganic acid, it is preferably set to approximately not lessthan 10%. If this concentration is too low, it may occur that thereaction speed of the hydrolysis is lowered or the hydrolytic reactioncannot proceed sufficiently. There is also no particular limitation tothe upper limit of the concentration. If hydrolysis is carried out bycharging a small quantity of the high-molecular material into sulfuricacid, the concentration of the inorganic acid is approximately 100%.

[0064] As the basic catalyst for the alkaline hydrolysis, inorganicbases, such as hydroxides, hydrogen carbonates, carbonates or acetatesof Li, Na, K or NH₄ may be used.

[0065] However, alkaline hydrolysis is in need of a higher temperaturethan in the case of the acidic hydrolysis described above, such that, ifthis temperature condition is once achieved, the reaction proceedsspeedily. The result is that the yielded high-molecular flocculant islowered in molecular weight, or the reaction of conversion of the cyangroup through a carbamoyl group to a carboxylic group or its saltproceeds at a time to render it difficult to control the introducedamount of ionic groups, that is carboxylic anions.

[0066] Therefore, the basic catalyst is not used from the outset of thereaction, and is preferably used in the second stage in case of thetwo-stage hydrolysis. That is, acidic hydrolysis by the acidic catalystis first carried out in the first stage to prescribe substantially theamount of the carbamoyl groups introduced and alkaline hydrolysis isthen carried out in the second stage in order to convert a furtherportion of the carbamoyl groups into carboxylic groups or salt thereof.

[0067] In any type of the alkaline hydrolysis, the high-molecularmaterial may be directly injected into inorganic acids, or into anaqueous alkaline solution of an inorganic base.

[0068] Alternatively, the above hydrolysis may be carried out in anorganic solvent, which may be a CS to C20 aliphatic chain hydrocarbonand/or cyclic hydrocarbon, C1 to C4 halogenated hydrocarbons, aromatichydrocarbons, ethers, ketones, esters, or non-protonic polar solvents,such as dimethyl sulfoxide, dimethyl formamide, tetrahydrofuran ordioxane.

[0069] The method for ultimate recovery of the high-molecular flocculantin the above-described manufacturing method differs with the system ofthe hydrolytic reaction. If, for example, the high-molecular material isdirectly charged into inorganic acid, it is possible to pour a solventin which the high-molecular flocculant is not soluble, such as acetone,into the reaction mixture in large quantities to re-precipitate theproduct. If the solvent is used during hydrolysis, the reaction productmay be obtained as an aqueous solution by neutralizing an excess acidiccatalyst or a basic catalyst and by distilling off the solvent.

[0070] With the reaction temperature for hydrolysis ranging between 0 to180° C., the reaction is allowed to proceed with practicallysatisfactory speed and controllability, although the reactiontemperature differs with the types of the high-molecular material usedas a starting material, the catalyst constituting the reaction system,and the presence or absence of the solvent. The reaction temperature ismore preferably 20 to 150° C. and most preferably 60 to 130° C.

[0071] The high-molecular flocculant, obtained as described above, is ofthe nonionic type by introducing the carbamoyl group and is of theanionic type by substituting carboxylic acid or carboxylates for aportion of the carbamoyl group.

[0072] Since the high-molecular flocculant of the present invention isat any rate of the nonionic, cationic or anionic type, it may be usedfor water processing in accordance with the usual method of exploitingthe nonionic, cationic or anionic type high-molecular flocculant.Alternatively, the high-molecular flocculant of the present inventionmay be used in conjunction with various other flocculants.

[0073] The usable nonionic high-molecular flocculants may be exemplifiedby a synthetic system, such as polyacrylic amide, polymethacrylic amideor polyoxyethylene, or natural systems, such as starch, guar gum,gelatine or the like sugar, or proteins.

[0074] The cationic high-molecular flocculants include quaternaryproducts of dialkyl aminoalkyl (meth)acrylate, where thequaternarification agents include methyl chloride, dimethyl sulfate andbenzyl chloride, or acid salts thereof, where acid salts includeinorganic acid salts, such as hydrochlorates or sulfates, and organicacid salts, such as acetates, polymers or copolymers thereof with(meth)acrylamide such as polymers of methyl chloride quaternary productof dimethyl aminoethyl acrylate or a copolymer thereof with acrylicamide. The cationic high-molecular flocculants also include quaternaryproduct of dialkyl aminoalkyl (meth)acrylic amide or an acid saltthereof, and polymers or copolymers thereof with (meth)acrylic amide,such as copolymer of methyl chloride quaternary product of dimethylamino propyl and acrylic amide. The cationic high-molecular flocculantsalso include cationated modified product of polyacrylamide, such asMannich modified product and Hoffman decomposition product ofpolyacrylamide, and an epihadrin-amine condensates, such as apolycondensate of epihadrin and C2 to C6 alkylene diamine. The cationichigh-molecular flocculants also include polydimethyl diallyl ammoniumchloride, polyvinyl imidazoline and/or salts thereof, dicyan diamidecondensates, such as a formalin condensate of dicyanamide and ammoniumchloride. The cationic high-molecular flocculants also includepolyethylene imine, its quaternary product or acid salts thereofpolyvinyl imidazole, its quaternary product or acid salts thereof,poly-4-vinyl benzyl trimethyl ammonium chloride, chitosan and its salts.The cationic high-molecular flocculants also include acidic hydrolyzatesof N-vinyl formamide/acrylonitrile copolymer, its quatemary product oracid salts, polyvinyl pyridine and tis quatermary product or acid salts.The cationic high-molecular flocculants further include an alkylenedichloride and polyalkylene polyamine condensates, aniline-formaldehydepolycondensates, polyhexameythylene thiourea acetate, polyamino acids,such as polylysin, polyglutamic acid and its salts.

[0075] The anionic high-molecular flocculants include partialhydrolyzates of polyacrylic amide and polymethacrylic amide, copolymersof acrylic acid or methacrylic acid and acrylic amide or methacrylicamide and salts thereof. The anionic high-molecular flocculants alsoinclude acrylic acid or methacrylic acid and acrylic amide ormethacrylic amide and 2-acryl amide-methyl propane sulfonic acid orvinyl sulfonic acid ternary copolymer and salts thereof. The anionichigh-molecular flocculants also include sodium salts of alginic acid,Guar gum, carboxymethyl cellulose and starch, polystyrene sulfonic acidand salts thereof. The anionic high-molecular flocculants furtherinclude sulfonated products and salts of polystyrene-based resin wastematerials, such as polystyrene, high-impact polystyrene, ABS resin, SANresin, nitrite rubber. The waste materials may contain up to 60 wt % ofpolyphenylene ether, polycarbonates, polyethylene terephthalates,polyamides and polyphenylene sulfide.

[0076] Of these high-molecular flocculants, sulfonated styrene-basedpolymers are desirable in that these exhibit high clarifying effect fora liquid suspension and can be fabricated using waste materials as thehigh-molecular flocculant of the present invention.

[0077] Examples of the styrene-based polymers used for thehigh-molecular flocculants include styrene-butadiene,styrene-acrylonitrile, styrene-butadiene-acrylonitrile,styrene-(meth)acrylic acid, styrene-(meth)acrylate (aliphatichydrocarbon having 1 to 4 carbon atoms),styrene-acrylonitrile-(meth)acrylate (aliphatic hydrocarbon having 1 to4 carbon atoms), styrene-butadiene(meth)acrylate (aliphatic hydrocarbonhaving 1 to 4 carbon atoms), styrene-malefic anhydride,styrene-acrylonitrile (meth)acrylate (aliphatic hydrocarbon having 1 to4 carbon atoms), styrene-butadiene-acrylonitrile and styrene-maleficanhydride. Preferred are styrene-butadiene, styrene-acrylonitrile,styrene-butadiene-acrylonitrile, styrene-malefic anhydride,styrene-acrylonitrile(meth)acrylic acid ester (aliphatic hydrocarbonhaving 1 to 4 carbon atoms) and styrene-butadiene (meth)acrylate(aliphatic hydrocarbon having 1 to 4 carbon atoms). Most preferred arestyrene-butadiene, styrene-acrylonitrile,styrene-butadiene-acrylonitrile, styrene-maleic anhydride.

[0078] The above-mentioned styrene-based polymers may be a newlyprepared material, that is a so-called virgin material, for producingthe high-molecular flocculant, waste materials from factories, retailstores or homes (waste materials) or the combination of the virginmaterial and the waste material. For re-exploitation of thepolystyrene-based resin products, manufactured in large quantities asgeneral-purpose resins, and for maintaining the earth's environments, itis more desirable to use the waste materials rather than the virginmaterials, as the styrene-based polymers.

[0079] If the waste materials are used, polymers other than theabove-mentioned styrene-based polymers may be contained in addition tothe styrene-based polymers. These other polymers may be exemplified bypolyphenylene ether, polycarbonates, polyphenylene sulfides andpolyethylene terephthalates. Most preferred are polyphenylene ether andpolycarbonates. The content of these other polymers is preferably notmore than approximately 60 wt %.

[0080] The above-mentioned styrene-based polymers are sulfonated in asolvent containing sulfonating agents. The sulfonated styrene-basedpolymer is converted into high-molecular flocculant by neutralizing thesulfone groups and subsequently distilling off the solvent and thesulfonating agent.

[0081] These sulfonating agents may be enumerated by sulfuric anhydride,fuming sulfuric acid, chlorosulfonic acid and concentrated sulfuricacid. These sulfonating agents may be used alone or in combination. Asfor the amount of addition of the sulfonating agents, these maypreferably be used in an amount of 0.5 to 2 mols and more preferably inan amount of 0.7 to 1.5 mol to 1 mole of the aromatic ring contained inthe styrene-based polymer (benzene ring in a side chain for astyrene-based resin and a benzene ring in the main chain for apolycarbonate resin). If added in an excessively small amount, thesulfonation agent cannot sufficiently sulfonate the styrene-basedpolymer. Thus, in such case, the high-molecular flocculant cannotdisplay its function as the high-molecular electrolyte. Conversely, ifadded in an larger quantity, gelated products are yielded during thesulfonating reaction or by-products, such as salts, are yielded inlarger quantities. Therefore, in this case, a large quantity ofimpurities are contained in the high-molecular flocculant, thus loweringits purity.

[0082] For sulfonating the strene-based polymer, the above-mentionedsulfonating agent may be used in conjunction with the Louis acid, whichmay be enumerated by alkyl phosphate, such as triethyl phosphate ortrimethyl phosphate, dioxane, acrylic anhydride, ethyl acetate, ethylpalmitate diethyl ether and thioxane. The amount of addition of theLouis acid is 0.01 to 2.0 mol and preferably 0.02 to 1.0 mol of thearomatic ring contained in the styrene-based polymer (benzene ring in aside chain for a styrene-based resin and a benzene ring in the mainchain for a polycarbonate resin). If added in an excessively smallamount, gelated products tend to be yielded during the sulfonatingreaction. If conversely the Louis acid is added in an excessive amount,the sulfonating reaction itself is retarded to lower the yield of thehigh-molecular flocculant to raise production cost.

[0083] The solvent used for sulfonating the styrene-based polymers maybe enumerated by C1 to C2 aliphatic halogenated hydrocarbons (preferably1,2-dichloroethane, chloroform, dichloromethane and 1,1-dichloroethane),and aliphatic cyclic hydrocarbons, preferably cyclohexane, methylcyclohexane and cyclopentane. These solvents may be used alone or as amixture. In mixing the solvents, there is no particular limitation tothe mixing ratio.

[0084] The above-mentioned solvents may be used as a mixture with othersolvents. These other solvents may be enumerated by paraffinichydrocarbons (with 1 to 7 carbon atoms), acetonitrile, carbon disulfide,tetrahydrofuran, tetrahydropyrane, 1,2-dimethoxy ethane, acetone,methylethylketone and thiophene. Preferred of the other solvents are C1to C7 paraffinic hydrocarbons, tetrahydrofuran, acetone andacetonitrile. Although there is no particular limitation to the mixingratio with the other solvents, the mixing ratio is preferably in a rangeo 1 to 100 vol %. The above-mentioned solvents may be recovered, such asby extraction or distillation, after the end of the sulfonating reactionof the styrene-based polymer, for re-use in the next sulfonatingreaction.

[0085] The above-mentioned anionic high-molecular flocculant can beobtained on mixing pre-set amounts of the sulfonating polymers,sulfonating agents and the solvent and continuing the sulfonatingreaction.

[0086] In the course of the sulfonating reaction, the concentration ofthe styrene-based polymer is preferably 0.1 to 30 wt % and morepreferably 0.5 to 20 wt %. If the concentration is lower than thisrange, it becomes difficult to introduce sulfone groups. If converselyconcentration is lower than this range, gelated products tend to beyielded during the sulfonating reaction or non-reacted substances areyielded in large quantities.

[0087] The reaction temperature for this sulfonating reaction is 0 to100° C. and preferably 15 to 80° C. If the reaction temperature is lowerthan this range in the sulfonating reaction, the sulfonating reaction isless liable to occur thus lowering the yield of the high-molecularflocculant.

[0088] In addition, in the present sulfonating reaction, the reactiontime duration, exclusive of the sulfonating agent dripping time, is 10minutes to 10 hours and preferably 30 minutes to 5 hours.

[0089] After the end of the sulfonating reaction of the solution, thesulfone groups are neutralized by a neutralizing agent and subsequentlythe solvent is distilled off to yield the desired high-molecularflocculant.

[0090] The neutralizing agent may be enumerated by oxides, hydroxides,carbonates, acetates, sulfonates, phosphates of basic compounds, such asalkali metals (sodium, lithium or potassium), alkali earth metals(magnesium or calcium), ammonia and a variety of amine compounds(primary to tertiary alkyl amines). This neutralizing agent is graduallyadded to the reaction system in the state of a solid or an aqueoussolution to neutralize the sulfone groups introduced into thestyrene-based polymer. The techniques for distilling off the solvent maybe the techniques of liquid separation or distillation.

[0091] With the high-molecular flocculant of the present invention, thusobtained, its molecular weight Mw needs to be 150000 to 600000. If themolecular weight of the styrene-based polymer in the high-molecularflocculant is less than 150000, not only is the flocculant effect forthe suspended substances in the liquid suspension lowered, but also thesuspended substances are dispersed. Conversely, if the molecular weightof the styrene-based polymer is not less than 600000, the suspendedsubstances are aggregated as coarse blocks such that optimum clarifyingeffects cannot be produced while the yielded cake is of high watercontent.

[0092] On the other hand, with the present high-molecular flocculant,not less than 40 mol % and preferably not less than 50 mol % of sulfonegroups are introduced into the styrene-based polymer. If the content ofthe sulfone groups in the styrene-based polymer is smaller than 40 mol%, the high-molecular flocculant is lowered in solubility in water, thussignificantly lowering the flocculant effect for the starting materialin the liquid suspension.

[0093] For introducing a desired amount of sulfone groups, it isdesirable for the styrene units to be contained in the styrene-basedpolymer in the high-molecular flocculant in an amount not less than 60mol % and preferably in an amount not less than 80 mol %. If the amountof styrene units in the styrene-based polymer is less than 60 mol %, itbecomes difficult to obtain the high-molecular flocculant, having theabove-mentioned amount of sulfone groups by the sulfonating reaction.

[0094] Besides these high-molecular flocculants, flocculants of naturalorigin may be used in conjunction with the high-molecular flocculant ofthe present invention. The flocculants of natural origin may beenumerated by ‘moroheiya’, its dried product and extracts, jelly-likeportion of the tomato seeds, its dried product or extract.

[0095] The ‘moroheiya’ is an annual grass of the genus Corcorus of theclass shinanoki cultivated in Arabian tropical areas such as Egypt,Syria, Jordan or Iran, and is used from old as food as green to yellowvegetables. The viscous acidic polysaccharides as main component of themoroheiya are used as flocculant.

[0096] Specifically, the flower, stalk, root or portions thereof ofmoroheiya are turned into paste which is used as the flocculant.Alternatively, the flower, stalk, root or portions thereof of moroheiyaare dried and pulverized in a mixer to produce powders which are used asthe flocculant. For drying the moroheiya, drying in the sun, air inshade, vacuum drying, hot air drying or freeze drying may be optionallyemployed.

[0097] The tomato is an annual plant of the class eggplant in thetemperate zone and used from old as food as green to yellow vegetables.It is the jelly-like portion around the tomato seed that is used as theflocculant.

[0098] Specifically, the jelly-like portion around the tomato seed ispulverized directly or in the dried state by a mixer to produce powderswhich are used as the flocculant. For drying, the techniques similar tothose for the moroheiya are used.

[0099] Further, the paste or powders of the moroheiya or thejelly-shaped portion around the tomato seed or its dried product areprocessed by extraction with water, warm water, hydrophilic organicsolvents (alcohols, ethers, N,N-dimethyl formamide or dimethyl sulfoxidesugar, or mixtures thereof, to produce a liquid extract which is used asthe flocculant. The liquid extract may also be fractionated or dried foruse as the flocculant. The liquid extract may preferably be water orwarm water.

[0100] The liquid extract may be re-precipitated in an organic solventas a poor solvent or the re-precipitated product may further be driedfor use as a flocculant.

[0101] The liquid extract may be freed from solid substances byfiltration, if so desired.

[0102] The alkalis may be ammoniac water, various amine compounds,sodium hydroxide, potassium hydroxide, potassium hydroxide and sodiumcarbonate. The acids may be organic acids, such as lactic acid, butyricacid, acetic acid or formic acid, and inorganic acids, such as sulfuricacid, hydrochloric acid and nitric acid.

[0103] Of course, the viscous portion of moroheiya and around tomatoseeds may directly be used as the flocculant. However, it is moreeffective to use the viscous portions as powders or liquid extract forfacilitating the diffusion in the processing liquid (liquid suspension).Also, the viscous portions of moroheiya and around tomato seeds,processed with extraction with water, warm water or water-solubleorganic solvents, are more meritorious than the directly dried viscousportions in flocculant effect per unit weight of the same solidsubstance.

[0104] If the polysaccharide component of moroheiya or the viscousportions around tomato seeds are pulverized or heated excessively, thesecomponents are lowered in flocculant activity due to the lowering of themolecular weight caused by cutting of the main and side chains or due toinsolubility in water caused by the intramolecular cross-linkingreaction.

[0105] The high-molecular flocculant of the present invention may beused in conjunction with any of the above-mentioned flocculants. If thehigh-molecular flocculant of the present invention is used inconjunction with reverse type high-molecular flocculants, specialtechniques need to be used for effective processing.

[0106] If, for example, the high-molecular flocculant of the presentinvention is charged positively, as when the high-molecular flocculanthas a molecular structure portion added to with amino compounds suchthat it is converted to an acid salt or a quaternary ammonium salt, andif the high-molecular flocculant is used in conjunction with theabove-mentioned anionic high-molecular flocculant, the two flocculantsare of opposite polarities in water. Therefore, the flocculants arepreferably used sequentially rather than as a mixture. Similarly, if thehigh-molecular flocculant of the present invention is chargedpositively, as when cyano groups are converted to carboxylic group viacarbamoyl group, and if the high-molecular flocculant is used inconjunction with the above-mentioned cationic high-molecular flocculant,the two flocculants are of opposite polarities in water. Therefore, theflocculants are again preferably used sequentially rather than as amixture.

[0107] If the two flocculants are used sequentially, any one of thecationic high-molecular flocculant and the anionic high-molecularflocculant may be charged first into water for processing. However, ifthe water for processing is sewage water, the cationic high-molecularflocculant is usually charged first, since the usual sewage water isgenerally processed with bactericidal treatment and hence the colloidsare charged to negative polarity.

[0108] In the water processing method of the present invention, thehigh-molecular flocculant of the present invention may also be used inconjunction with inorganic flocculants or flocculation assistant agents.

[0109] The inorganic flocculants may be enumerated by aluminum sulfate,aluminum polychloride, sodium aluminate, ferrous chloride, ferricchloride, ferric sulfate, copper chloride, modified basic aluminumsulfate (LACS) and activated silica.

[0110] The flocculation assistant agents may, for example, be enumeratedby slaked lime, sodium silicate, bentonite and flyash.

[0111] These ingredients are generally added in amounts of 0.001 to 2000ppm and preferably 0.1 to 500 ppm, related to waste water, depending onthe concentration of the starting material or the type of thedehydrating equipment.

[0112] Although there is no limitation to the type of the water forprocessing in accordance with the present invention, maximum effects canbe produced when the water for processing is highly contaminated water,such as plant waste water having inorganic particles as the startingmaterial.

[0113] The amount of addition of the high-molecular flocculant of thepresent invention to water for processing differs with the compositionof the water for processing and with the combination with other startingmaterial and the flocculation assistant agents. If the amount ofaddition is too small, the particles of the starting material cannot beflocculated sufficiently, whereas, if the amount is too large, theproportion of the high-molecular flocculant not contributing toflocculation is increased to lead to wastage of the high-molecularflocculant to give rise to renewed water contamination. The desirablerange of addition is generally 0.001 to 2000 ppm and more preferably 0.1to 500 ppm.

[0114] For processing waste water using the high-molecular flocculant ofthe present invention, coagulating agents, chelate resins, chelatingagents, activated charcoal, ozonized water, ion exchange resins,water-absorptive resins, aqueous hydrogen peroxide, chlorine, liquidchlroline, sodium hypochlorite, chlorine dioxide, bleaching powder,chlorinated isocyan, diatomaceous earth, optical catalysts, such astitanium oxide, and biological processing agents, may be used.

[0115] Also, a variety of dehydrates, such as belt press dehydrator,centrifugal dehydrator or a screw press may be used. Dehydratedproducts, such as cakes, may be used for land filling using knowntechniques or converted into fuel or composts.

EXAMPLES

[0116] The present invention is hereinafter explained with reference toillustrative Examples based on experimental results.

[0117] [Modification of Cyano-group Containing High-molecular WasteMaterials by Addition of Amino Compounds]

[0118] First, the high-molecular waste material containing cyano groupsis reacted with amino compounds to produce a high-molecular flocculantin order to check into its properties.

[0119] The following three high-molecular waste materials, containingcyano groups, we used in the following experiments.

[0120] The resulting powders were analyzed by Fourier transform IRabsorption spectrum (FT-IR) and nuclear magnetic resonance (NMR)spectrum. It was found that 80 mol % of cyano groups in the solidreaction product had been converted to imidazoline rings and that theseimidazoline rings were not hydrolysed. The resulting powders were alsosoluble in water.

[0121] These powders were termed a high-molecular flocculant A. Thishigh-molecular flocculant A was of the nonionic type.

Example 2

[0122] An imidazoline ring containing polymer was obtained in the sameway as in Example 1 except using 3.5 g of ethylene diamine as an aminocompound.

[0123] This polymer was dissolved in water and methyl chloride wasinjected into the resulting mass. The resulting product was reacted at40° C. for two hours to yield an aqueous solution of a methyl chloridequaternary salt polymer of imidazoline, while non-reacted methylchloride was distilled off on heating.

[0124] The resulting product was termed a high-molecular flocculant B.This high-molecular flocculant B was of the cationic type.

Example 3

[0125] 1.0 g of small pieces of nitrile resin waste material b wasdissolved in 100 ml of dimethyl sulfoxide (DMSO). To the resulting masswere dripped 2.3 g of ethanolamine at room temperature. The resultingmass was stirred in situ and heated to 100° C. to carry out the reactionfor 12 hours.

[0126] After the end of the reaction, the reaction solution was pouredinto ethanol and precipitated. After filtration, the resulting productwas rinsed with methanol and dried in vacuo at room temperature. Theabove processing yielded a polymer in which 85% of the cyano groups werereplaced by an imino structure.

[0127] The resulting product was termed a high-molecular flocculant C.This high-molecular flocculant C was of the cationic type.

Example 4

[0128] An imino group containing polymer was obtained in the same way asin Example 3 except using 2.8 g of butylamine as an amino compound.

[0129] This polymer was dissolved in water and admixed with an aqueoussolution of dilute sulfuric acid to set pH to 4.0 to obtain a sulfatepolymer solution.

[0130] The resulting product was termed a high-molecular flocculant D.This high-molecular flocculant D was of the cationic type.

Example 5

[0131] A high-molecular flocculant was produced in the same way as nExample 2 except using SAN resin waste material c as a startingmaterial.

[0132] This high-molecular flocculant was termed a high-molecularflocculant E which was of the cationic type.

Example 6

[0133] The high-molecular flocculant C was dissolved in water and theresulting aqueous solution was heated at 90° C. for 15 hours. After theend of the heating, the aqueous solution was dried to produce powders,for which the Fourier transform IR absorption spectrum (FT-IR) andnuclear magnetic resonance (NMR) spectrum were measured. By thesemeasurements, it was confirmed that 70 mol % of the imino structure washydrolysed and converted to an amide structure.

[0134] This high-molecular flocculant was termed a high-molecularflocculant F which was of the nonionic type.

Example 7

[0135] 0.05 g of sulfur powdered and 1.0 g of small pieces of wasteacrylic fiber material a were added to 20 g of ethylene diamine andreaction was carried out at 110° C. for six hours. After the end of the110° C. reaction, non-reacted ethylene diamine was distilled off bydistillation in vacuo and the residual mass was dissolved in water andprecipitated with acetone.

[0136] The precipitates were then filtered and dried in vacuo at roomtemperature to produce brown powders. For these powders, the Fouriertransform IR absorption spectrum (FT-IR) and nuclear magnetic resonance(NMR) spectrum were measured. By these measurements, it was confirmedthat 42 mol % of the cyano groups of the solid reaction product wereconverted to imidazoline rings, and 18 mol % thereof were convertedto—amino ethyl acrylamide which was a hydrolizate.

[0137] This polymer was then dissolved in water and a dilute aqueoussolution of hydrochloric acid was added to the solution to give anaqueous solution of a hydrochlorate polymer.

[0138] This high-molecular flocculant was termed a high-molecularflocculant G which was of the nonionic type.

[0139] [Evaluation of Flocculant Performance]

[0140] The flocculant performance of these high-molecular flocculants Ato G were evaluated.

[0141] In the following set of test examples, the following flocculantswere used with a view to comparison or use with the inventive products.

[0142] Nonionic high-molecular flocculant H: commercial polyacrylamide

[0143] cationic high-molecular flocculant I: methyl chloride quaternaryproduct of commercial polydimethyl amino ethyl acrylate (potent cationictype)

[0144] anionic high-molecular flocculant J: commercial polyacryl amidepartial hydrolyzate (mid anionic type)

[0145] sulfonate of waste resin material K: sodium polystyrene sulfonate(starting material: expanded styrene, sulfonation ratio: 80 mol %)

[0146] hydrolyzate L of waste fiber: polyacrylonitrile hydrolyzate(acrylic fibers processed with sodium hydroxide)

[0147] flocculant M of natural origin: dried pulverized moroheiya leaves

[0148] Evaluation Test 1

[0149] A 1 wt % aqueous solution of kaoline was prepared and used as aliquid suspension for evaluation of flocculation (this solution ishereinafter termed a liquid suspension). 100 ml of this liquidsuspension were charged into a measuring cylinder with a co-plug havinga capacity of 200 ml. The high-molecular flocculant and conventionalhigh-molecular flocculants for comparison were dripped into the liquidsuspension using measuring pipettes. The dripping amounts were set sothat the concentration of the high-molecular flocculant in the liquidsuspension was equal to 4 ppm.

[0150] After dripping, the measuring cylinder was stopped with the plugand turned upside down and restored repeatedly ten times. The measuringcylinder was then restored to the stationary state to measure the rateof precipitation of the suspended particles and the turbidity of thesupernatant liquid. The measured results are shown in Table 1.

[0151] Acrylic fiber waste material a

[0152] waste material of acrylic fibers for underwear containing notless than 95 mol % of acrylonitrile

[0153] nitrile resin waste material b

[0154] waste material of vessels for cosmetics containing not less than90 mol % of acrylonitrile

[0155] SAN (styrene-acrylonitrile) resin waste material c

[0156] waste material of 8 mm cassette caging (transparent portions)containing 40 mol % of acrylonitrile

[0157] The above three waste materials were processed into small-sizedchips for use as starting material. The acrylic fiber waste material wassevered by scissors into small-sized chips with each side 5 mm or lessin length, while the nitrite resin waste material b and the SAN resinwaste material c were severed by a cutter type crusher into small-sizedchips not larger than 16 mesh for use as starting material.

Example 1

[0158] 4 g of 1,3-propane diamine, 0.03 g of sulfur powders and 1.0 g ofsmall pieces of acrylic fiber waste material a were charged into 40 g ofcyclohexane and stirred in situ to carry out an addition reaction at 60°C. for four hours.

[0159] A green solid substance, precipitated on the bottom of thereaction vessel, was taken out and dissolved. The resulting solution waspoured into a large quantity of acetone and precipitated.

[0160] The precipitate was then filtered and dried in vacuo at roomtemperature to yield pale yellow powders. TABLE 1 high appellation A C FG H molecular ion type Nonionic type flocculant rate of precipitation 2321 22 20 16 (m/n) turbidity (ppm) 12  8 10 13 32

[0161] It is seen from table 1 that nonionic high-molecular flocculants,modified by addition of the amino compound to the cyano group, showedmore satisfactory results in the rate of precipitation and in turbidityof the supernatant liquid than the conventional nonionic flocculant andexhibited superior flocculating performance.

[0162] Evaluation Test 2

[0163] The processed liquid, obtained on primary flocculation of wastewater from an electronic parts plant (pH 6.5, SS 1.5 wt %) was used as aliquid suspension for evaluation of flocculation.

[0164] 100 ml of the liquid suspension were charged into a measuringcylinder with a co-plug, having a capacity of 200 ml and each flocculantwas dripped into the liquid suspension using a measuring pipette. Thedripping amount was set so that the high-molecular flocculant in theliquid suspension will be of the concentration equal to 2 ppm. If twosorts of the liquid suspension were used together, these flocculantswere mixed together so that the above concentration will be equal to 1ppm.

[0165] After dripping, the measuring cylinder was stopped with the plugand turned upside down and restored repeatedly ten times. The measuringcylinder was then restored to the stationary state to measure the rateof precipitation of the suspended particles, turbidity of thesupernatant liquid and the water content of the cake obtained afterfiltration by a filter cloth. The measured results are shown in Table 2.TABLE 2 high appellation A A + J F + J J molecular ion type Anionicflocculant rate of precipitation 23 28 25 16 (m/h) turbidity (ppm) 12  810 32 water content (%) 73 70 68 75

[0166] It is seen from table 2 that the high-molecular flocculant of thepresent invention was superior to the conventional anionic flocculant inthe rate of precipitation, turbidity of the supernatant liquid and inwater content of the cake. It has also been seen that the high-molecularflocculant of the present invention can further be improved inflocculation performance by using it as a mixture with commercialanionic flocculants.

[0167] Evaluation Test 3

[0168] A mixed sludge from a sewage processing plant (pH, 6.2; SS 2.5 wt%) was put to a jar test.

[0169] First, 0.5 wt % per SS of a cationic high-molecular flocculantwas added to the sludge being agitated by a jar tester and agitated forflocculation. If two sorts of the high-molecular flocculant were used asa mixture, the charged amounts of the flocculants were set to 0.2 wt %per SS. To the resulting product was further added 0.2 wt % of theanionic high-molecular flocculant per SS and agitated for flocculation.

[0170] The flocculated mass was then allowed to stand and measurementwas then made of the rate of precipitation of suspended particles,turbidity of the supernatant liquid and the water content of the cakeobtained on filtration. The measured results are shown in table 3. TABLE3 cationic flocculant B D E G B + M I I I anionic flocculant — J K L J —J K precipitation rate 37 41 44 42 45 24 29 27 (m/h) turbidity (ppm) 2722 25 23 20 43 36 33 water content (%) 73 72 71 72 71 77 76 75

[0171] It is seen from table 3 that the high-molecular flocculant of thepresent invention was superior to the conventional anionic flocculant inthe rate of precipitation, turbidity of the supernatant liquid and inwater content of the cake both when used alone and when used inconjunction with the anionic flocculant. It has also been seen that thehigh-molecular flocculant of the present invention can further beimproved in flocculation performance by using it as a mixture withflocculants of natural origin.

[0172] [Modification of Waste High-molecular Material by Hydrolysis ofCyano Groups]

[0173] The following four high-molecular materials were used as basematerials for hydrolysis in the respective Examples.

[0174] waste acrylic fibers d

[0175] waste acrylic fibers for underwear containing not less than 90mol % of acrylonitrile;

[0176] waste nitrile rubber e

[0177] waste oil-resistant rubber and hose material containing not lessthan 40 mol % of acrylonitrile;

[0178] waste nitrile resin f

[0179] waste vessels for cosmetics containing not less than 90 mol % ofacrylonitrile;

[0180] SAN (styrene-acrylonitrile) waste resin g

[0181] waste battery casing material containing not less than 30 mol %of acrylonitrile;

[0182] The waste material d was severed with scissors into small pieceseach having a side measuring 5 mm or less.

[0183] The waste material e was freeze-pulverized to small pieces eachmeasuring 32 mesh or less.

[0184] The waste materials f and g were pulverised to small piecesmeasuring 32 mesh or less using a cutter type pulveriser.

Example 8

[0185] 0.6 g of the waste material d was charged into 30 g of 96%sulfuric acid and agitated in in situ to carry out acidic hydrolysis at50° C. for two hours. The waste material d was completely dissolved insulfuric acid.

[0186] Next, this mixture was poured in a large quantity of acetone toyield a white precipitate, which was further washed twice or thrice withacetone and dried.

[0187] The dried powders were analyzed by measurement with the Fouriertransform IR absorption spectrum (FT-IR) and nuclear magnetic resonance(NMR) spectrum. By these measurements, it was confirmed that not lessthan 90 mol % of the cyano groups in the waste material d were convertedto carbamoyl groups and that carboxylic groups were generated under theabove-mentioned reaction conditions. These powders were also readilysoluble in water.

[0188] These powders were termed a high-molecular flocculant N. The iontype of this high-molecular flocculant N was the nonionic type.

Example 9

[0189] The acid hydrolysis was carried out by the same method as inExample 8 except using the waste material e and setting the reactiontemperature and reaction time to 80° C. and 4 hours, respectively.

[0190] The FT-IR and NMR measurements, conducted on the resultingpowders, revealed that not less than 90 mol % of the cyano groups in thewaste material e were converted to carbamoyl groups and that nocarboxylic groups were generated under the above-mentioned reactionconditions. These powders were also readily soluble in water.

[0191] These powders were termed a high-molecular flocculant O . The iontype of this high-molecular flocculant O was the nonionic type.

Example 10

[0192] The acid hydrolysis was carried out by the same method as inExample 8 except using the waste material f and setting the reactiontemperature and reaction time to 80° C. and 4 hours, respectively.

[0193] The FT-IR and NMR measurements, conducted on the resultingpowders, revealed that not less than 90 mol % of the cyano groups in thewaste material f were converted to carbamoyl groups and that nocarboxylic groups were generated under the above-mentioned reactionconditions. These powders were also readily soluble in water.

[0194] These powders were termed a high-molecular flocculant P. The iontype of this high-molecular flocculant P was the nonionic type.

Example 11

[0195] The acid hydrolysis was carried out by the same method as inExample 8 except using the waste material g and setting the reactiontemperature and reaction time to 80° C. and 4 hours, respectively.

[0196] The FT-IR and NMR measurements, conducted on the resultingpowders, revealed that not less than 90 mol % of the cyano groups in thewaste material g were converted to carbamoyl groups and that nocarboxylic groups were generated under the above-mentioned reactionconditions. These powders were also readily soluble in water:

[0197] These powders were termed a high-molecular flocculant Q. The iontype of this high-molecular flocculant Q was the nonionic type.

Example 12

[0198] 1 g of the waste material d was charged into 40 g of cyclohexaneand, as the temperature of the reaction system was controlled to 25 to30° C., 1.8 g of sulfuric anhydride was dripped over 30 minutes. Afterthe end of dripping, agitation was continued for further 30 minutes. 30g of water were added to the reaction system to carry out hydrolysis at30° for one hour.

[0199] The reaction mixture was distilled in vacuo to remove cyclohexaneand the residual liquid was adjusted to pH of 6 to produce ahigh-molecular aqueous solution. The FT-IR and NMR measurements,conducted on the resulting high-molecular aqueous solution, revealedthat not less than 90 mol % of the cyano groups in the waste material dwere converted to carbamoyl groups and that no carboxylic groups weregenerated under the above-mentioned reaction conditions. These powderswere also readily soluble in water.

[0200] These powders were termed a high-molecular flocculant R. The iontype of this high-molecular flocculant R was the nonionic type.

Example 13

[0201] To a 1%-aqueous solution of the high-molecular flocculant N,obtained in Example 8, sodium hydroxide (NaOH) equivalent to 50 mol % ofcarbamoyl groups of the high-molecular flocculant N was added to carryout alkaline hydrolysis at 80° C. for one hour.

[0202] The FT-IR and NMR measurements, conducted on the resultinghigh-molecular aqueous solution, revealed that, of the carbanoyl groupsof the high-molecular flocculant N, 90 mol % of the added amount ofNaOH, corresponding to 45 mol % of the initial carbamoyl group content,were converted to sodium salt type carboxylic groups.

[0203] These powders were termed a high-molecular flocculant S. The iontype of this high-molecular flocculant S was the anionic type.

Example 14

[0204] To a 1%-aqueous solution of the high-molecular flocculant R,obtained in Example 12, sodium hydroxide (NaOH) in an equimolar amountto carbamoyl groups of the high-molecular flocculant R was added tocarry out alkaline hydrolysis at 80° C. for one hour.

[0205] The FT-IR and NMR measurements, conducted on the resultinghigh-molecular aqueous solution, revealed that, of the carbamoyl groupsof the high-molecular flocculant R, 90 mol % of the added amount ofNaOH, corresponding to 90 mol % of the initial carbamoyl group content,were converted to sodium salt type carboxylic groups.

[0206] These powders were termed a high-molecular flocculant T. The iontype of this high-molecular flocculant T was the anionic type.

[0207] The high-molecular flocculants obtained in Examples 8 to 14 areindicated collectively in Table 4. TABLE 4 Starting material andAcrylonit rile Content of Appellation and hydrolysis type (catalysts forcontent in functional groups ion type of high- hydrolysis are given instarting material after modification molecular Ex. parentheses) (mol %)(mol %) State of products flocculant 8 Waste acrylic fibers: d;acidic >90 —CN <9  Water-soluble, N: nonionic hydrolysis (concentrated—CONH₂ >81 white powders sulfuric acid) —COOH — 9 Waste nitrile rubber:e; acidic >40 —CN <4  Water-soluble, O: nonionic hydrolysis(concentrated —CONH₂ >36 white powders sulfuric acid) —COOH — 10 Wastenitrile rubber: f; acidic >90 —CN <9  Water-soluble, P: nonionichydrolysis (concentrated —CONH₂ >81 white powders sulfuric acid) —COOH —11 Waste styrene-acrylonitrile >30 —CN <3  Water-soluble, Q: nonionicresin: g; acidic hydrolysis —CONH₂ >27 white powders (concentratedsulfuric acid) —COOH — 12 Waste acrylic fibers: d; acidic >90 —CN <9 High-molecular R: nonionic hydrolysis (sulfuric anhydride) —CONH₂ >81aqueous solution —COOH — 13 Product N of Ex. 8; acidic >90 —CN <9 High-molecular S: nonionic hydrolysis (concentrated —CONH₂ >45 aqueoussolution sulfuric acid) + alkaline —COOH >36 hydrolysis (NaOH) 14Product R of Ex. 12; acidic >90 —CN <9  High-molecular T: nonionichydrolysis (sulfuric anhydride) + alkaline —CONH₂ >8  aqueous solutionhydrolysis (NaOH) —COOH >73

[0208] In Table 4, the content of the as-modified functional groupsrefers to the total number of mols of the monomeric units making up thehigh-molecular material.

[0209] [Evaluation of Flocculating Performance]

[0210] Next, the flocculating performance of the high-molecularflocculants N to T was evaluated.

[0211] In the following set of the evaluation tests, the following twocommercial high-molecular flocculants U, V were used with a view tocomparison and conjunctive use with the inventive products.

[0212] High molecular Flocculant U

[0213] partial hydrolyzate of polyacrylamide portion (hydrolyzationrate, 20 mol %), anionic type

[0214] High molecular Flocculant V

[0215] Methyl chloride quaternary product of dimethyl amino ethylacrylate, potent cationic type

[0216] Evaluation Test 4

[0217] 0.2 wt % of aluminum sulfate as added to a 4 wt %-aqueoussolution of kaoline to give a colloidal liquid suspension forflocculation evaluation (referred to hereinafter as liquid suspension).

[0218] 100 ml. of this liquid suspension were charged into a measuringcylinder with a co-plug having a capacity of 200 ml. The high-molecularflocculants N to T and conventional high-molecular flocculants forcomparison were dripped into the liquid suspension using measuringpipettes. The dripping mounts were set so that the concentration of thehigh-molecular flocculant in the liquid suspension was equal to 5 ppm.

[0219] After dripping, the measuring cylinder was stopped with the plugand turned upside down and restored repeatedly ten times. The measuringcylinder was then restored to the to the stationary state to measure therate of precipitation of the suspended particles and the turbidity ofthe supernatant liquid.

[0220] The measured results are shown in Table 5. TABLE 5 high- a N O PQ R S T U molecular ion nonionic anionic flocculant rate of 15 13 14 1316 17 18 10 precipitation (m/h) turbidity (ppm) 35 45 43 48 32 28 25 50

[0221] On comparison of the flocculating performance of thehigh-molecular flocculants N to T of the present invention according toion types, the anionic type high-molecular flocculants S and T aresuperior to the nonionic type high-molecular flocculants N to R.Therefore, in flocculating the colloidal system in which kaoline isflocculated primarily with aluminum sulfate used in the present Example,the anionic type high-molecular flocculants S and T may be said to besuperior to the hydrogen bonded type nonionic high-molecular flocculantsN to R.

[0222] Thus, on comparing the flocculating performance of the sameanionic type flocculants, the anionic type high-molecular flocculants Sand T of the present invention are superior to the conventional anionictype high-molecular flocculant. Moreover, the conventional product U wasinferior in performance the nonionic type high-molecular flocculants Nto R of the present invention.

[0223] This indicated the superior flocculating performance of theinventive products.

[0224] Evaluation Test 5

[0225] 500 ppm of aluminum sulfate were added to the waste water of anelectronic parts plant (pH, 4.8; mass of the floating substance (SS) of1.2 wt %) to prepare a liquid suspension for flocculation evaluation(referred to hereinafter as liquid suspension).

[0226] 100 ml of this liquid suspension were charged into a measuringcylinder with a co-plug having a capacity of 200 ml. An aqueous solutionof the high-molecular flocculant was dripped into the liquid suspensionusing measuring pipettes. The high-molecular flocculants used here werethe nonionic high-molecular flocculants N, O, anionic high-molecularflocculants S, T and the conventional anionic high-molecular flocculantU.

[0227] The inventive products N, O and S were used as an 50-50 mixturewith the conventional product U, whilst the inventive product T and theconventional product U were used alone. The high-molecular flocculantswere added in amounts which would give concentration of 10 ppm in theliquid suspension. Thus, if the two flocculants were used inconjunction, the inventive product and the conventional product are usedeach in the concentration of 5 ppm.

[0228] After dripping, the measuring cylinder was stopped with the plugand turned upside down and restored repeatedly ten times. The measuringcylinder was then restored to the stationary state to measure the rateof precipitation of the suspended particles and the turbidity of thesupernatant liquid. The precipitate yielded was dehydrated on a filtercloth to measure the water content in the cake.

[0229] The measured results are shown in table 6. TABLE 6 high-molecularInventive appellation N O S T — flocculant ion type nonionic anionicconventional U — U (anionic) rate of precipitation (m/h) 25 22 28 22 20turbidity (ppm) 12 15 10  8 30 water content of cake after 71 73 70 6875 dehydration (ppm)

[0230] On comparing the case of using the high-molecular flocculant T ofthe present invention to that of using the conventional high-molecularflocculant U, as cases of using the sole high-molecular flocculant, theinventive product is superior in flocculating performance. It is notedthat these two flocculants are both of the anionic type. Theconventional product, inferior by itself to the inventive product, isimproved in flocculating performance on combination with the inventiveproducts N, O and S. This verified superior flocculating performanceproper to the inventive product.

[0231] However, in any of the above cases of combined use, theflocculating performance of the present invention in which anionichigh-molecular flocculants T was used by itself could not be surpassedas far as turbidity was concerned. This is probably ascribable to thefact that the inventive product is smaller in molecular weight andhigher in anionic efficiency than the conventional product.

[0232] Similar effects could be obtained when the commercialhigh-molecular flocculant used on mixing with the inventive product waschanged to the nonionic type.

[0233] Evaluation Test 6

[0234] A jar test was conducted on a mixed sludge from a sewageprocessing plant (pH, 6.6; SS, 2.8 wt %). Specifically, as the abovemixed sludge was agitated by the jar tester, the commercialhigh-molecular flocculant V was added in a first step to the agitatedsludge at a rate of 0.6 wt %. Then, at a second step, the high-molecularflocculants P, Q or T or the conventional anionic high-molecularflocculant U was added each at a rate of 0.15 wt % to the suspendedparticles.

[0235] After agitation, the liquid suspension was allowed to standstationarily and measurements were made of the rate of precipitation ofthe suspended particles and turbidity of the supernatant liquid. Also,the produced precipitates were dehydrated on a filter cloth to measurethe water content of the cake.

[0236] The measured results are shown in Table 7. TABLE 7 high-Inventive appellation {circle over (2)}P {circle over (2)}Q {circle over(2)}T — molecular ion type Nonionic anionic flocculant Conventional{circle over (1)}*V (cationic) {circle over (1)}V (cationic) {circleover (2)}P (anionic) rate of precipitation (m/h) 41 38 44 33 turbidity(ppm) 25 28 22 38 water content of cake after 72 73 71 75 dehydration(ppm)

[0237] In general, if the composition of the suspended particles iscomplex or cannot be known correctly, static charges of the colloidalparticles is also thought to be nonuniform. It is therefore thought tobe effective to use the high-molecular flocculant of the cationic typeand that of the nonionic type simultaneously. On comparison of thecombination of the conventional cationic type flocculant and theconventional cationic type flocculant to the combination of the cationicand anionic type inventive products, it has been found that thecombination of the inventive products manifested superior flocculanteffects.

[0238] In particular, the optimum flocculating effects can be obtainedon combining the conventional high-molecular flocculant and theinventive high-molecular flocculant.

[0239] Although cationic high-molecular flocculant cannot as a principlebe manufactured on hydrolysis of cyano groups, waste water processingcan be achieved more effectively by using the inventive flocculant incombination with the cationic commercial flocculant.

[0240] Although the preferred embodiments of the present invention andthe results of evaluating tests have been explained in the foregoing, itshould be noted that these embodiments have been given for illustrationpurposes and are not intended for limiting the scope of the invention.Specifically, the present invention can be optionally modified as to thetypes of the starting materials for the high-molecular flocculant orconditions for addition reaction, hydrolytic reaction, acid saltformation or water processing.

What is claimed is:
 1. A high-molecular flocculant having a molecularstructure portion comprised of an organic and/or inorganic aminocompound added to at least a portion of cyano groups contained in ahigh-molecular material.
 2. The high-molecular flocculant as claimed inclaim 1 wherein said inorganic amino compound is at least one ofammonia, hydrazine and hydroxylamine.
 3. The high-molecular flocculantas claimed in claim 1 wherein said inorganic amino compound is at leastone of a primary amine substituted by C1 to C12 hydrocarbon group and asecondary amine substituted by C1 to C12 hydrocarbon group.
 4. Thehigh-molecular flocculant as claimed in claim 1 wherein said inorganicamino compound is a polyamine having two or more amino groups.
 5. Thehigh-molecular flocculant as claimed in claim 4 wherein the molecularstructure portion having the polyamine added thereto includes animidazoline ring.
 6. The high-molecular flocculant as claimed in claim 1wherein at least a portion of the molecular structure portion forms asalt with one of an inorganic acid, an organic acid, a halogenatedhydrocarbon and a sulfuric acid ester.
 7. The high-molecular flocculantas claimed in claim 1 wherein at least a portion of the molecularstructure portion is further hydrolysed.
 8. The high-molecularflocculant as claimed in claim 1 wherein said high-molecular materialcontains acrylonitrile as a monomer unit.
 9. The high-molecularflocculant as claimed in claim 8 wherein said high-molecular material isat least one selected from the group of acrylic fibers, nitrite resin,styrene-acrylonitrile resin, acrylonitrile-butadiene-styrene resin,acrylonitrile-styrene-acrylic resin, acrylonitrile-chlorinatedpolyethylene-styrene resin, nitrite rubber and acrylonitrile-butadienerubber.
 10. The high-molecular flocculant as claimed in claim 1 whereinsaid high-molecular material contains not less than 15 mol % of thetotal monomer units.
 11. The high-molecular flocculant as claimed inclaim 1 wherein said high-molecular material is contained in a wastematerial used up for other purposes.
 12. A method for producing ahigh-molecular flocculant comprising: reacting a high-molecular materialcontaining a cyano group with an inorganic and/or organic aminocompound; and introducing a molecular structure portion having saidamino compound added to at least a portion of the cyano group.
 13. Themethod for producing a high-molecular flocculant as claimed in claim 12wherein at least one selected from the group of ammonia, hydrazine andhydroxylamine is used as said amino compound.
 14. The method forproducing a high-molecular flocculant as claimed in claim 13 wherein anorganic amino compound is used as said amino compound and wherein animidazoline ring is formed as said molecular structure portion.
 15. Themethod for producing a high-molecular flocculant as claimed in claim 12wherein one of an inorganic acid, an organic acid and a halogenatedhydrocarbon is acted on said molecular structure portion for convertingat least a portion of the molecular structure portion into a salt. 16.The high-molecular flocculant as claimed in claim 12 wherein at least aportion of the molecular structure portion is further hydrolysed. 17.The high-molecular flocculant as claimed in claim 12 wherein ahigh-molecular material containing acrylonitrile as a monomer unit isused as the high-molecular material.
 18. The high-molecular flocculantas claimed in claim 17 wherein at least one selected from the group ofacrylic fibers, nitrite resin, styrene-acrylonitrile resin,acrylonitrile butadiene-styrene resin, acrylonitrile-styrene-acrylicresin, acrylonitrile-chlorinated polyethylene-styrene resin, nitriterubber and acrylonitrile-butadiene rubber is used as said high-molecularmaterial.
 19. The high-molecular flocculant as claimed in claim 12wherein a high-molecular material containing not less than 15 mol % ofthe total monomer units is used as said high-molecular material.
 20. Thehigh-molecular flocculant as claimed in claim 12 wherein ahigh-molecular material contained in a waste material used up for otherpurposes is used as said high-molecular material.
 21. A method for waterprocessing comprising: charging into water for processing ahigh-molecular flocculant having a molecular structure portion comprisedof an inorganic and/or organic amine compound added to at least aportion of cyano groups contained in a high-molecular material.
 22. Themethod for water processing as claimed in claim 21 wherein saidhigh-molecular flocculant is used in conjunction with at least one of anonionic high-molecular flocculant, an anionic high-molecular flocculantand a cationic high-molecular flocculant.
 23. The method for waterprocessing as claimed in claim 22 further comprising: sequentiallycharging said high-molecular flocculant and the anionic high-molecularflocculant into the water for processing.
 24. A high-molecularflocculant in which at least a portion of cyano groups contained in ahigh-molecular material has been converted into carbamoyl groups. 25.The high-molecular flocculant as claimed in claim 24 wherein a furtherportion of the carbamoyl groups is converted into carboxyl groups orsalts thereof.
 26. The high-molecular flocculant as claimed in claim 24wherein said high-molecular material contains acrylonitrile as a monomerunit.
 27. The high-molecular flocculant as claimed in claim 26 whereinsaid high-molecular material is at least one selected from the group ofacrylic fibers, nitrite resin, styrene-acrylonitrile resin,acrylonitrile-butadiene-styrene resin, acrylonitrile-styrene-acrylicresin, acrylonitrile-chlorinated polyethylene-styrene resin, nitriterubber and acrylonitrile-butadiene rubber.
 28. The high-molecularflocculant as claimed in claim 24 wherein said high-molecular materialcontains not less than 15 mol % of the total monomer units.
 29. Thehigh-molecular flocculant as claimed in claim 24 wherein saidhigh-molecular material is contained in a waste material used up forother purposes.
 30. A method for producing a high-molecular flocculantcomprising: hydrolysing a high-molecular material containing cyanogroups to convert at least a portion of the cyano groups into carbamoylgroups.
 31. The method for producing a high-molecular flocculant asclaimed in claim 30 wherein said hydrolysis is carried out in one stepin the presence of an acidic catalyst.
 32. The method for producing ahigh-molecular flocculant as claimed in claim 30 wherein said hydrolysisis carried out in two steps, namely a first step employing an acidiccatalyst and a second step of employing a basic catalyst, and wherein,in said second step, a further portion of the carbanoyl groups isconverted into carboxylic groups or salts thereof.
 33. Thehigh-molecular flocculant as claimed in claim 30 wherein ahigh-molecular material containing acrylonitrile as a monomer unit isused as the high-molecular material.
 34. The high-molecular flocculantas claimed in claim 33 wherein at least one selected from the group ofacrylic fibers, nitrite resin, styrene-acrylonitrile resin,acrylonitrile, butadiene-styrene resin, acrylonitrile-styrene-acrylicresin, acrylonitrile-chlorinated polyethylene-styrene resin, nitriterubber and acrylonitrile butadiene rubber is used as said high-molecularmaterial.
 35. The high-molecular flocculant as claimed in claim 30wherein a high-molecular material containing not less than 15 mol % ofthe total monomer units is used as said high-molecular material.
 36. Amethod for processing water comprising: charging into water forprocessing a high-molecular flocculant comprised of a high-molecularmaterial at least a portion of cyano groups of which has been convertedinto carbamoyl groups.
 37. The method for water processing as claimed inclaim 36 wherein said high-molecular flocculant is used in conjunctionwith at least one of a nonionic high-molecular flocculant, an anionichigh-molecular flocculant and a cationic high-molecular flocculant. 38.The method for water processing as claimed in claim 37 furthercomprising: sequentially charging said high-molecular flocculant and theanionic high-molecular flocculant into the water for processing.
 39. Themethod for water processing as claimed in claim 36 further comprising:charging into the water for processing the high-molecular flocculant afurther portion of carbamoyl groups of which have been converted intocarboxylic groups or salts thereof.